Cameras, such as a camera and a projector, involve a necessity for replacement of a lens. Hence, a lens mount structure used for mounting and demounting a main body, such as a camera, to a lens barrel has hitherto been known (see JP-A-5-072618 and JP-A-9-211656).
For instance, as shown in FIG. 4, a related-art lens mount structure used for mounting a lens barrel to a camera main body and demounting the same has a flange portion 101 formed along an outer periphery of a base body of a lens barrel 100. A cylindrical mount 105 is disposed at the front of a camera main body 103. The mount 105 is screw-engaged with the front of the camera main body 103. The flange portion 101 of the lens barrel is sandwiched between the front of the camera main body 103 and the mount 105, to thus attach the lens barrel 100 to the camera main body 103.
In the related-art lens mount structure, a reference surface 102 is set on a ground side of the flange portion. The reference surface 102 is brought into contact with a mount surface 104 on the front of the camera main body 103, thereby aligning the lens optical axis of the lens barrel. In the related-art structure shown in FIG. 4, there is provided a mechanism for retaining and adjusting the flange by means of screw-engagement, whereby the reference surface 102 of the flange portion is brought into contact with the mount surface of the camera main body 103, to thus align the lens optical axis of the lens barrel.
However, according to the related-art lens mount structure, even when the cylindrical mount 105 is tightly screw-engaged with the front of the camera main body, if a nominal clearance exists, the lens barrel tilts under its own weight, because the center of gravity of the lens barrel is situated at a position closer to a front edge thereof than to the position where the flange is formed. The reference surface 102 of the lens barrel fails to come into intimate contact with the mount surface 104 of the camera main body 103, resulting in misalignment of the lens optical axis of the lens barrel.